Question: Express your answer in scientific notation. $2.2 \cdot 10^{6} - 4.3 \cdot 10^{5} = $
Answer: $\phantom{=}{2.2 \cdot 10^{6}} - 4.3 \cdot 10^{5}$ $={22 \cdot 10^{5}} - 4.3 \cdot 10^{5}$ $= (22-4.3)\cdot10^{5}$ $=17.7\cdot10^{5}$ $=1.77\cdot10^{6}$